1. Field of the Invention
The present invention is generally related to a roller for impressing a desired pattern in a malleable surface, such as concrete and the like.
2. Description of the Related Art
In the past, a system has been proposed (U.S. Pat. No. 5,033,906) for imprinting a pattern on concrete through the use of a roller having a plurality of spaced running ridges and spaced header ridges defined thereon. The running and header ridges define an impression pattern on the roller surface for impressing a corresponding simulated masonry pattern on the concrete. The ridges are configured such that multiple patterns may be rolled adjacent to one another by providing one end of the roller with an end ridge and an opposite end of the roller without an end ridge. The header and running ridges are formed integrally upon a roller core which is filled with a liquid material to add weight to the roller. Additionally, the roller of the '906 patent uses a vibrator to induce vibrations throughout the apparatus in order to enhance the impression-making ability thereof.
An alternative system has been proposed (U.S. Pat. No. 4,105,354) in which a pattern forming wheel is used with uncured concrete surfaces. The wheel includes a generally cylindrical frame which is large enough to accommodate a worker in a walking position. The frame supports a plurality of rigid blades carried about its outside surface, wherein the blades are configured to provide a desired pattern. A walkway is provided on the inside surface of the frame to support the worker. The frame may be gripped by the worker and serve as a hand-hold if desired. The weight of the worker is combined with the weight of the wheel to aid in driving the blades into the surface of the slab to a predetermined depth. A plurality of tools of the same diameter may be peripherally linked together to increase simultaneous pattern imprinting width so that the combination of linked tools will span the width of large slabs.
An alternative system has been proposed (U.S. Pat. No. 3,832,079) in which an apparatus is driven over partially cured concrete to form a pattern therein. The system of the '079 patent includes a plastic film or other suitable release agent which permits the apparatus to be driven on the concrete to form the pattern without removing the surface of the concrete when it is withdrawn. The '079 patent generally comprises a roller with a series of patterns constructed from blades that conform to the pattern to be pressed into the concrete. As a substitute for the plastic sheet, the '079 patent sprays releasing agents, such as silicones and tetrafluoralethylenes, on the roller blades or on the concrete to prevent binding and gouging of the pavement.
However, these prior art systems have met with limited success. The system of the '906 patent only offers a single pattern integrally within the concrete impressing system. Hence, if it is desirable to use a different pattern, an entirely separate roller must be formed. Similarly, in the system of the '354 patent, separate wheels must be formed for each desired pattern. In the system of the '079 patent, the entire roller assembly pulled by the tractor must be replaced to change the pattern impressed into the concrete. The necessity of separate impressing systems for each pattern render it unduly expensive to use multiple patterns.
Further, each of the '534, '079, and '906 patents require that the concrete partially cure before the pattern is formed therein. This is due in part to the fact that heretofore, plastics have been used between the roller and concrete which were undesirably thick. These overly thick plastics resist the downward forces exerted by the pattern forming ridges of the roller upon the concrete. Thus, overly thick plastics inhibit pattern formation. To compensate for this plastic inhibiting effect, the prior art rollers add additional weight to the roller to force the pattern forming ridges and the plastic into the concrete.
Further, the thick plastics used by the prior art rollers prevent the formation of properly formed edges along each indentation within the concrete. When the plastic is forced into the grooves in the concrete, the plastic applied excessive force along the edges of each groove. The excessive force applied by these somewhat rigid plastics degraded the pattern by deforming the upper edges of each brick within the concrete. To properly form these edges, the prior art systems require the concrete to be partially cured before using the roller. This partially cured concrete, once impressed, is able to withstand the forces of the plastic upon the corners. However, when impressing a pattern into partially concrete further increases the need for additional weight within the roller and the need for a waiting period between the time that the concrete is poured and the time that the roller is used.
Further, the system of the '079 patent removes the sheet of plastic from the concrete immediately after the pattern is pressed therethrough. Consequently, the system of the '079 patent is unable to provide a slick finish upon the concrete. The texture of the concrete is determined by the curing time period during which the plastic is left on the concrete. Thus, if a rough textured concrete is desired, the plastic may be peeled off immediately. However, if a slick surface is desired upon the concrete, the plastic must remain for a significant portion of the curing time, such as overnight. The slicker the finish upon the concrete, the better it resists penetration by water. Also, the initial curing time required by the prior art systems before impressing the pattern limits the system's ability to provide a slick surface.
Moreover, once a concrete slab has been laid, it is often desirable to paint or stain the concrete to a color other than the concrete's natural color. To effect such changes in color, a variety of systems have been proposed. For instance, the concrete may be painted with ordinary stain, or enamel-based or latex-based paint once it cures sufficiently. However, in the past these stains and paints have quickly and easily chipped off of the concrete. Further, it has been unduly difficult to lay down a smooth and even layer of stain or paint.
Alternatively, it has been proposed to add pigmentations, stains or paints to the concrete prior to pouring it. However, the desired color additive must be introduced before or while the concrete is within the mixer which causes the interior of the mixing tank to become similarly colored. The pigmentations, paints, and stains added to the concrete while in the mixer further interfere with the long term operation of the mixing and pouring equipment.
The need remains in the industry for an improved pattern forming roller and method for painting such concrete. It is the object of the present invention to meet these needs, and to overcome drawbacks previously experienced.